Piston ring



I J. E. NORWOOD.

.PISTON RING.

APPLICATION FILED ShPT-3,1918.

Patented Jan. 24, 1922 72 7717-5 08/717 1J JOHN E. NDBWQOID, 0F BALTIMiERE, HARYLAE-l'lh.

PISTON RING.

Specification of Letters Patent.

Patented can. 24, 1922.

Application flied fieptem'ber 3, 1918. Serial 1%. 25%,38

To all whom it may concern:

Be it known that I, JOHN E. Noawoon, a citizen on the United States, residing at Baltimore, in the county of Baltimore, State of Maryland, have invented certain new and useful Improvements in Piston Rings; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which itiappertains to make and use the same.

This invention relates to piston rings and more particularl of that class wherein the ring is provide with a circumscribing oil receiving channel in its outer periphery, which in operation, holds the oil in position to seal the ring.

In a rin of this character as ordinarily constructec, and in which the ring contacts with the cylinder at both sides of the oil groove, the contacting surface of the ring at both sides of the groove is of material transverse extent so that the oil on the face of thecylinder does not readily flow to a groove.

It is the object of the present invention to provide a construction wherein the contacting surface of the ring at one side of the groove will have a minimum transverse extent so that said contacting surface while holding the oil against too ready flow from the groove will yet permit of the How of oil into the groove more readily because of the cylinder pressure against the oil.

A further object of the invention is to provide an improved construction wherein such oil as may pile up in front of the ring will be directed to the groove of the ring instead of passing to the 1 ring receiving channel of the piston.

In the drawings:

Figure 1 is a section taken longitudinally through a portion of the'cylinder and piston of an explosive engine equipped with a ring embodying the present invention.

Figure 2 is a sectional perspective view or the ring shown in Figure 1.

Figure 3 is a view similar to Figure 1, showing a lesser portion-of the cylinder and piston and illustrating a modification of the ring.

Figure :l: is a View similar to Figure 3 showing a further modification.

Referring to the drawings there is shown a portion of the cylinder 5 of an explosive engine in which is disposed a piston 6 having the usual circumscribing channel 7 to receive a packing ring.

Thepacking ring embodying the present invention consists of a short hollow cylinder 8 of the usual resilient material and with the usual opening to permit of compression and expansion of the ring radially.

The end walls 9 and 10 of the ring are flat and at ri ht angles to the inner periphery 11 an these end walls 9 and 10 closely but slidably fit against the correspondlng side walls 12 and 13 of the ring receiving channel 7 of the piston.

In the outer periphery of the ring'S is formed a circumscribing groove which in the embodiment illustrated has one wall 14 I at right angles to the outer periphery 15 of the ring while the other wall 16 extends from the bottom of the wall 14 and at an acute angle thereto and terminates at the outer periphery of the ring. From the outer periphery 15. of the ring at the line of intersection thereof by the groove wall 16 there extends a bevel 17 to the end face 12 of the ring. This bevel is straight and at an acute angle to the inner surface of the wall of the cylinder 5. The inner end of this bevel terminates substantially at the periphery of the piston.

This ring in practice is disposed in the piston adjacent the end that receives the explosion pressure and the ring is disposed with its end bevel 17 in the direction of the explosion chamber of the cylinder.

In practice, as the piston moves against compression the film of oil on the contacting face of the cylinder is not scraped oflf by the portion of the contacting surfaces of the ring lying between the bevel 17 and. the groove wall 16. This is first by reason of the fact that the film of oil is very thin and clings to the cylinder wall by capillary action and with sufficient tenacity to over come the comparatively slight inclination to scrape that is had by this very narrow sur' face. Again. as soon as any scraping begins there is a piling up of the oil in the angle between the bevel 1? and the wall of the cylinder and against thissmall ridge of oil there impinges the cylinder pressure which increases under the compression and serves to force past this narrow face and into the groove of the piston the excess of oil thus piled up, that was distributed onto the face of the cylinder during the just previous intake stroke of the piston,

It will be noted that the portion 17 of the ring is disposed at an angle to the face 15 of the ring and is located at the other slde of the groove from the face 15. The extensive contacting surfaces of the ring between the groove and the end 10 of the ring however prevents so free a movement of the mug over the oil which therefore is collected 1n the groove of the ring to form an oil seal.

Again by reason of the bevel 17 the scraping of oil from the surfaces of the cylinder does not occur until the end face 12 of the piston ring is beyond the line of scrap ng and thus, the scraped oil instead of being deflected at right angles into the slight in terspace between the end wall 9 of the ring and the corresponding wall 12 of the channel 7 initially piles up within the angle and its return flow is across this interspace.

Referring to Figure 3 of the drawings, there is shown a modifiation wherein, instead of forming thebevel 17, the ring 8 has an oil retaining groove bounded by the radial wall 14 and the second wall 16 at an acute angle thereto. A second oil receiving groove is formed which is bounded by a radial wall 20 that touches the periphery 15 of the ring at substantially the same line with the wall 16 to form the same minimum contacting surface as in the first instance that will let the oil into the groove between the walls 14 and 16 under pressure of the expansion and will retard its outflow. From the base of the wall 20 of the second groove there extends at an acute angle thereto the wall 21- that meets the end faces 9 of the ring inwardly of the outer periphery 15' of the ring. Thus, the oil may freely enter this second groove. In this construction the first named groove holds the oil as a seal while the second groove will arrest the oil that would otherwise be deflected into the intcrspace bcwcen the end 9 of the ring and contacting wall of the ring receiving channel of the piston.

I11'Figure4 of the drawings there is shown a further modifimition wherein the groove and bevel as shown in Figure l is embodied in a two-piece ring. This two-piece ring includes the annular members A and B. The member B has a cylindrical outer pcriphcry 15" that contacts with the wall of the cylinder 5". ()nc end face ll) of the-menu ber B contacts with the wall 13 of the ring receiving channel 7 of the piston. The other end face 14 of the member B. adiacent the peripheral face 15 is at right angles to the axis of the ring and corresponds to the groovewall 14 of Figure l.

A rabbct C is formed in the intersection of the face 14 with the inner peripherv of the member B in this rabbet is fitted the corresponding portion D of the ring member A which portion D is of correspondinglv reduced external diameter. From the base of the wall 14' the member A extends at an acute angleto said wall 14:" as shown at 16", to touch the face of the cylinder wall 5". Thence the member A is beveled at 17" to the end face 9 of the member A that contacts with the wall 12" of the ring receiving channel.

In the use of this two-part ring, the member A is disposed in the direction of compression and oil passes by capillary action and by pressure, across the line of intersection of the faces 16" and 17 to the oil pocket or groove between the faces 16" and 14-". The oil packs into this groove. Now the oil will of course flow into this groove past this narrow edge readily but will not pass readily between the face 15" and the wall of the cylinder. The consequence is that the subsequent pressure past this narrow edge against the wall will be distributed over the faces 16 and 14" and in accordance with the well known hydraulic principles, will exert a strong pressure to slide the ring members with respect to each other and cause the member A to bear tightly against the wall 12 and the face 10"- to bear tightly against the wall 13. -Thus is the composite ring caused to completely fill the channel from side to side and prevent leakage.

What is claimed is:

1. A piston ring for internal combustion engines the same comprising a pair of annula'r members, the respective annular members each having a flat axial end face, the fiat faces of the respective members being adapted to bear against opposite walls of the -piston groove. the said members being also in contact with each other throughout their length along annular surfaces, said annular surfaces being in the form of an annular step so that each member has a contacting surface in cylimlrical form and one which is plane and at right angles to the axis, one said ring member also having a cylindrical surface which contacts the cylinder wall, the other having a peripheral edge which like wise contacts the c vlinder wall, the edge being formed by the intersection of surfaces placed at acute angles to the axis, the cylindrical surface of the other ring member being provided by surfaces at right angles to ll 1 axis so that there is formed between the members a peripheral groove with a straight Leeeeee an acute angie te the fqrniing an in beveled, i. e. having a peripheral pertien 10 dined surface leading from the axial end formed at an acute angle to the axis. surface of the ring to the said edge. In testimony whereof, 1 21th:: my signature 3. A. spring piston. ring for internal (101m in the presence of two witnesses. 5 bustion engines the same having a continuous 1 JOHN E. I )R OFD. annular peripheral groove, a scraplng edge A A on one side of the groove, a flat contacting Witnesses:

surface on the other side of the groove, an ROBERT L. GRAFFLIN,

axial end. surface adjacent the edge being H. VERNON LEITCH. 

